How to mute an Audio Capture Filter of webcam in DirectShow?

If you want to mute an audio capture of webcam, you have to query IAMAudioInputMixer interface on its INPUT PIN, and then use put_Enable method to disable it.

Both the audio capture filter itself and its input pin have IAMAudioInputMixer interface, but the put_Enable / get_Enable methods are implemented on input pin only.

Reference in MSDN:
http://msdn.microsoft.com/en-us/library/ms783820.aspx